The present invention relates to a food processor according to the preamble of claim 1.
A known food processor of this type (U.S. Pat. No. 4,362,219) comprises weighing arms which can be pulled out at the front. A recess provided in the forward portion of the weighing arm in this extended position accepts a weighing basket which is suspended therein by the operator, and the tilting movement which the weighing arm performs, against the action of a flat spring, when being loaded by the material to be weighed, is transformed, via a toothing of a gearing, into a rotary movement which is transmitted to a code disk whose rotation is then measured electrically, by means of suitable circuit arrangements which may also comprise a microprocessor, and translated into a weight value which is then displayed by suitable display means provided on the food processor. The weighing bowl may then be relocated for having the food ingredients processed therein by the food processor.
Quite apart from the troublesome operations which cannot be avoided in the case of this known food processor and which consist in particular in the fact that one first has to estimate roughly the weight of the material in the bowl in order to pull out the desired weighing arm--the two arms provided being assigned to two different maximum weights--one probably also has to accept considerable losses in accuracy caused by frictional and hysteresis effects, and the like, due to the initial mechanical translation of the deflection of the weighing arm and the subsequent electric coding process. An additional problem is seen in the circumstance that the known appliance does not permit continuous measurements to be effected, for example by resetting of the measuring result, as the weighing bowl has to be changed if ingredients to be added in smaller quantities, for example, are to be weighed. Consequently, it is not possible to add all ingredients required for one recipe in succession and to determine their quantity by a consecutive weighing process.
This food processor, therefore, makes use only of a separate weighing system, without realizing a concept really integrating a food processor with a weighing system.
In this respect, the food processor known from German Utility Patent 18 94 430 can be regarded as a further development insofar as a weighing system, though operating in a very rough manner only, is integrated in one of the feet of the appliance, the structure being such that one of the feet is designed as a sliding tube and can be pushed into the housing of the appliance against the action of a biasing spring.
A toothing provided on the outer periphery of the vertically sliding tube forming one of the feet of a food processor is engaged by a rotary pinion which simultaneously supports a mechanical pointer the outer end of which is then in a position to indicate weight differences, moving along a rather coarsely graded, semicircular scale.
Consequently, it is in fact possible with this food processor to load the weighing system successively during food preparation, by filling in the ingredients in succession, so that differential measurements are also possible simply by memorizing former positions occupied by the pointer. However, more exact measurements are absolutely impossible with such a food processor, if only because frictional influences beyond any control are encountered in connection with the sliding properties of the pipe/foot of the appliance and in the area of the toothing, so that any thought of a weighing accuracy in the range of grams must be excluded from the very beginning.
Finally, a toy food processor with associated scales has been known from U.S. Pat. No. 3,171,634. In this case, the food processor is arranged at the end of a scale balance which is lowered in response to the weight of the food processor which movement is transferred to a pointer, via a double toggle lever system, which is thereby caused to move along a scale without numbering.
When preparing food with the aid of food processors, for example when preparing (bread) doughs or when mixing food according to predetermined recipes, it is frequently indispensable that the stated quantities or the ingredients, related to their weight, be closely adhered too. When preparing food for diabetics, for example, this is an absolute necessity for reasons of health.
On the other hand, the food processors of interest here are electrically driven which means that the recipients of the ingredients which are to be thoroughly mixed and brought into the desired form, for example by a mixing or kneading process, frequently have to stand considerable forces in the areas of engagement between the respective bowl and the machine, during such mixing or kneading processes.
If the ingredients required for a recipe are weighed separately, outside the food processor, or only on the latter (compare the before-mentioned U.S. Pat. No. 4,362,219), and are then filled into the common bowl, this leads to a considerable amount of work as the dish of the scales has to be cleaned for each ingredient, an operation which causes a lot of work in particular when liquid ingredients are to be weighed.
Therefore, it frequently happens that the weight of an ingredient is not determined at all, or only roughly, so that one cannot always be sure that the desired results will be actually achieved. It also happens that kitchen scales are either not available at all, or employed at a different place, and in addition kitchen scales do not always permit very exact measurements, most of them being based on the spring balance principle and using a little precise analog indication system.
Now, it is the object of the present invention to simplify decisively the process of determining the weight of foodstuff ingredients which are to be subjected to a subsequent processing operation in a food processor, either alone or together with other ingredients.